Radiotelegraph system



Dec, 9

W N name E. C. HANSON RADI OTELEGR APH SYSTEM Filed March 11, 1920 2 Sheets-Shet Patented Dec. 9, 1924.

um'rso STATES EARL C. HANSON, OF WASHINGTON, DISTRICT OF COLUMBIA.

RADIOTELEGRAPH SYSTEM.

Application filed. March 11, 1920.

To all whom it may concern:

Be it known that I, EARL C. Hanson, a citizen of the United States, residing at lVashington, District of Columbia,'have invented certain new and useful Improvements in Radiotelegraph Systems, of which the following is a specification.

This invention relates to the transmission of radio or wireless signals, and more particularly to high speed transmission.

The primary object of my invention is to provide an arrangement for initially record-- ing and subsequently transmitting telegraph signals automatically by radio.

A further object of this invention is to provide means for recording signals at one speed and subsequently transmitting said signals at a different speed.

My invention, as will be appreciated by radio engineers, departs radically from systems heretofore proposed for conducting long distance radio traffic. The invention makes practical the continuous operation of long distance radio stations on twenty four hour schedules. The invention is illustrated diagrammatically in one of its forms in the accompanying drawings, wherein- Figure-1 shows a recording circuit to be used for making an initial record on the recording element of an automatic transmigter here illustrated as a telegraphone; an

Figure 2 shows a circuit for operating the controlling device of a high frequency generator, by means of the amplified signal previously recorded on the telegraphone.

Referring particularly to the diagram shown in Figure 1, reference character 1 represents a thermionic vacuum tube arranged to generate oscillations. These oscillations are preferably of audio frequency and are produced in the oscillating circuit including a coupling transformer comprising windings 2 and 3. 4 and 5 are the usual plate and filament batteries for the tube 1. Relay 7 controlled by the key 9 with battery 8 operates to close armature 6 which completes the electric circuit through winding 10 inductively coupled to coils 2 and 3, and in circuit with windings 11 of the telegraphone 12. The telegraphone has the usual moving steel wire 14 operated by reel mechanism 15.

In Figure 2 reference character 14 represents the moving steel wire passing by the reproducing magnets 18 of the telegraphone Serial No. 365,125.

16. Windings 18 are electrically associated with the input circuit of vacuum tube 22 through an audio frequency transformer having windings 20 and 21. The filament of the tube 22 is heated by battery 25. The battery 24 supplies energy to the plate circuit of tube 22. The output of vacuum tube 22 is connected through audio frequency transformer windings 23 and 26 to the input of high power vacuum tubes 30 and 31 connected in parallel. The usual condenser 27 and grid leak 28 are placed in the grid circuits. v

The battery 32 supplies energy to heat the filaments of the vacuum tubes 30 and 31. High capacity condenser 33 shunts the plate circuit comprising the high voltage battery 34 and the controlling winding 36 of the magnetic amplifier 35. 37, and 37 of magnetic amplifier 35 and condensers 38, 38 and 40 are connected to coupling coil 41 ,to form the local antenna control circuit.

The antenna circuit 42 is coupled through winding 46 to inductance 41 and windings 45 which are supplied with radio frequency energy delivered by the radio frequency alternator 43.- The alternator 43 is driven by motor 44 as a prime mover.

The operation of the system is as follows: Consider, for example, that a high power transmitting station is to be oper ated to maintain radio telegraphic communication at 150 words per minute over a long distance. The problem solved by this invention is the successful control. of the high power transmitting energy at this rate of transmission.

In Figure 1 is shown an electric circuit for enabling the telegraph operator to re cord a message on the telegraphone or automatic transmitter at the speed of approximately twenty five words per minute. The

vacuum tube circuit in Figure 1 oscillates continually at preferably an audio frequency and the key 9 manipulated by the operator functions to close the relay 6 which completes the circuit allowing the audio frequency current to energize magnets 11 and hence magnetize the moving steel wire 14 at the frequency of the oscillating circuit and in accordance with the signals to be sent.

In the reproducing and transmitting process shown in Figure 2 the moving steel wire 14 on which the signals were previously recorded is run at a higher speed to increase the volume of traffic With the distant co-opcrating station. Therefore, the frequency and the speed of the signal energy impressed on the windings of magnets 18 is proportionately increased. This energy is amplified through a vacuum tube power amplifier similar to the type used for Wireless telephony, The tubes and 31 are connected in parallel and their circuits so adjusted as to function as rectifiers, and, therefore, when an audio frequency is impressed on the grid circuits of these tubes, there is produced in the plate circuit a rectified alternating current which will have a direct current component. The magnetic amplifier 35 will be operated by this direct current Variationin the plate circuit. A high capacity condenser 33 is shunted across the plate-circuit to bypass the audio frequency component in the plate circuit. The operation of the magnetic amplifier and the transmitting circuits associated therewith is described by Dr. E. F. W. Alexanderson in the Institute of Radio Engineers Proceedings, January 1916 and in the Proceedings of the American Institute of Electrical Engineers, October 1919.-

It is to be understood that in lieu of the high frequency alternator herein shown any other suitable means for producing high frequency oscillations may be employed.

It is to be further understood that the automatic transmitter here described as a telegraphone may be substituted by any of the well known forms of automatic tape or film transmitters wherein the control circuits are arranged within the scope of the appended claim.

What I claim is In a high speed radio telegraphic transmitting system the combination of a source of sustained, oscillations, apparatus for magnetically controlling the radiation of energy from an antenna system, a telegrapho'ne wire, means for recording an extended series of signal characters on said wire at a given speed and frequency, means for reproducing said signal characters atan increased speed and frequency, and a circuit for amplifying and rectifying the signal energy whereby adirect current variation affects'said magnetic control. apparatus in accordance with the signal characters on said telegraphone Wire.

EARL c. HANSON. 

